Chemical treatment of semiconductor substrates

Abstract

A method is disclosed for removing liquids from a semiconductor substrate by contacting the liquid on the substrate with a liquid which attracts the liquid on the substrate, separating the liquids from the substrate, and inducing a phase transition in a layer on the substrate. In particular, the method is applicable to removing water from a water-containing layer on the substrate by contacting the layer with a hygroscopic liquid. Trenches on a substrate can be isolated by filling the trenches with a water-containing gel formed by reacting silane and hydrogen peroxide. The gel is contacted with sulfuric acid to remove a portion of the water from the gel before annealing to form silica in the trenches. Unlike filled trenches formed by conventional technology, there are no voids in the bottom of the trenches. The method is also applicable to forming dielectric layers which cover metal lines, low-dielectric layers, and interlayer dielectric layers. The liquid may be applied to the substrate by chemical vapor deposition or by spin-applying.

I claim:  
     
       1. A method of removing at least a portion of a first liquid from a liquid-containing layer on a semiconductor substrate, comprising: 
       forming a first layer containing said first liquid on the semiconductor substrate;  
       forming a second layer on the first layer, said second layer comprising a second liquid; and  
       contacting said first layer with said second liquid which attracts said first liquid in said first layer, thereby transferring at least a portion of the first liquid out of said first layer into said second liquid, wherein said second liquid remains in said second layer; and  
       separating said second liquid from said first layer, thereby removing at least a portion of said first liquid from said first layer; and  
       inducing a phase transition in said first layer during or after said contacting.  
     
     
       2. The method of  claim 1 , further comprising: 
       annealing said substrate and said first layer.  
     
     
       3. The method of  claim 2 , wherein the first layer undergoes the phase transition during said annealing. 
     
     
       4. A method of isolating plural trenches on a substrate, comprising: 
       placing said substrate in a chamber;  
       introducing silicon-containing vapor and hydrogen peroxide vapor into said chamber;  
       reacting said silicon-containing vapor with said hydrogen peroxide vapor to form a liquid layer comprising silicon-containing oligomers and water on the substrate, said liquid layer filling at least a portion of said trenches;  
       contacting said liquid layer with a hygroscopic liquid to remove at least a portion of said water in said liquid layer by transferring said at least a portion of said water out of said liquid layer and into said hygroscopic liquid;  
       separating said hygroscopic liquid from said liquid layer; and  
       heating said liquid layer to a temperature sufficient to form a solid comprising silica in at least a portion of said trenches.  
     
     
       5. The method of  claim 4 , wherein said silicon-containing vapor comprises silane. 
     
     
       6. The method of  claim 4 , wherein said hygroscopic liquid is selected from the group consisting of sulfuric acid, phosphoric acid, and a hygroscopic organic solvent. 
     
     
       7. The method of  claim 4 , wherein said hygroscopic liquid comprises sulfuric acid. 
     
     
       8. The method of  claim 7 , wherein said hygroscopic liquid comprising sulfuric acid is contacted with said liquid layer at a temperature between 0 and 300° Centigrade. 
     
     
       9. The method of  claim 7 , wherein said hygroscopic liquid comprising sulfuric acid is contacted said liquid layer at a temperature between 100 and 200° Centigrade. 
     
     
       10. The method of  claim 7 , wherein said hygroscopic liquid comprising sulfuric acid is contacted said liquid layer at a temperature of approximately 150° Centigrade. 
     
     
       11. The method of  claim 7 , wherein said hygroscopic liquid comprising sulfuric acid is at a concentration of between 50 and 98 weight percent sulfuric acid. 
     
     
       12. The method of  claim 7 , wherein said hygroscopic liquid comprising sulfuric acid is at a concentration of approximately 98 weight percent sulfuric acid. 
     
     
       13. The method of  claim 4 , wherein said liquid layer is heated to a temperature between 100 and 1100° Centigrade. 
     
     
       14. The method of  claim 4 , wherein said liquid layer is heated to a temperature between 300 and 800° Centigrade. 
     
     
       15. The method of  claim 4 , wherein said liquid layer is heated to a temperature of approximately 400° Centigrade. 
     
     
       16. A method of treating a semiconductor substrate comprising: 
       placing the substrate in a chamber;  
       introducing silicon-containing vapor and hydrogen peroxide vapor into the chamber;  
       reacting said silicon-containing vapor with said hydrogen peroxide vapor to form a liquid layer comprising silicon-containing oligomers and water on the substrate; and  
       treating said liquid layer with a hygroscopic liquid, thereby removing at least a portion of said water in said liquid layer by transferring said at least a portion of said water out of said liquid layer and into said hygroscopic liquid.  
     
     
       17. The method of  claim 16 , further comprising separating said hygroscopic liquid from said liquid layer. 
     
     
       18. The method of  claim 17 , further comprising heating said liquid layer after separating said hygroscopic liquid from said liquid layer. 
     
     
       19. The method of  claim 18 , wherein said heating forms a solid comprising silica from said liquid layer. 
     
     
       20. The method of  claim 19 , wherein said solid comprising silica forms an interlayer dielectric layer on said substrate. 
     
     
       21. The method of  claim 20 , wherein said interlayer dielectric layer comprises a trench. 
     
     
       22. The method of  claim 21 , further comprising filling said trench with a metal. 
     
     
       23. The method of  claim 19 , wherein said substrate comprises a plurality of trenches. 
     
     
       24. The method of  claim 23 , wherein said solid comprising silica isolates said substrate between said trenches. 
     
     
       25. The method of  claim 19 , wherein said substrate comprises a plurality of metal lines on said substrate. 
     
     
       26. The method of  claim 25 , wherein said solid comprising silica forms a dielectric layer over said plurality of metal lines. 
     
     
       27. The method of  claim 16 , wherein said hygroscopic liquid is selected from the group consisting of sulfuric acid, phosphoric acid, and a hygroscopic organic solvent. 
     
     
       28. The method of  claim 16 , wherein said hygroscopic liquid comprises sulfuric acid. 
     
     
       29. The method of  claim 28 , wherein said liquid layer is treated with said hygroscopic liquid comprising sulfuric acid at a temperature between 0 and 300° Centigrade. 
     
     
       30. The method of  claim 28 , wherein said liquid layer is treated with said hygroscopic liquid comprising sulfuric acid at a temperature between 100 and 200° Centigrade. 
     
     
       31. The method of  claim 28 , wherein said liquid layer is treated with said hygroscopic liquid comprising sulfuric acid at a temperature of approximately 150° Centigrade. 
     
     
       32. The method of  claim 28 , wherein said hygroscopic liquid comprising sulfuric acid is at a concentration of between 50 and 98 weight percent sulfuric acid. 
     
     
       33. The method of  claim 28 , wherein hygroscopic liquid comprising sulfuric acid is at a concentration of approximately 98 weight percent sulfuric acid. 
     
     
       34. The method of  claim 16 , wherein said silicon-containing vapor comprises methyl silane. 
     
     
       35. The method of  claim 34 , further comprising heating said liquid layer to a temperature sufficient to convert said liquid layer to a solid comprising silicon oxide. 
     
     
       36. The method of  claim 35 , wherein said solid comprising silicon oxide forms a low-dielectric layer. 
     
     
       37. A method of treating a semiconductor substrate in a chamber, said method comprising: 
       applying a first liquid comprising silicon onto said substrate and applying a hygroscopic second liquid onto said substrate after applying said first liquid;  
       contacting said first liquid comprising silicon and said second liquid with a third liquid which attracts said second liquid, thereby removing at least a portion of said second liquid; and  
       separating said third liquid from said first liquid comprising silicon on said substrate.  
     
     
       38. The method of  claim 37  wherein said hygroscopic second liquid is selected from the group consisting of sulfuric acid, phosphoric acid, and a hygroscopic organic solvent. 
     
     
       39. The method of  claim 37 , wherein said hygroscopic second liquid comprises sulfuric acid. 
     
     
       40. The method of  claim 39 , wherein said first liquid is contacted with said hygroscopic second liquid comprising sulfuric acid at a temperature between 0 and 300° C. 
     
     
       41. The method of  claim 39 , wherein said first liquid is contacted with said hygroscopic second liquid comprising sulfuric acid at a temperature between 100 and 200° C. 
     
     
       42. The method of  claim 39 , wherein said first liquid is contacted with said hygroscopic second liquid comprising sulfuric acid at a temperature of approximately 150° C. 
     
     
       43. The method of  claim 39 , wherein said hygroscopic second liquid comprising sulfuric acid is at a concentration between 50 and 98 weight percent sulfuric acid. 
     
     
       44. The method of  claim 39 , wherein said hygroscopic second liquid comprising sulfuric acid is at a concentration of approximately 98 weight percent sulfuric acid. 
     
     
       45. The method of  claim 37 , wherein said first liquid comprising silicon comprises silicon dioxide. 
     
     
       46. The method of  claim 37 , wherein said applying comprises spin applying said first liquid comprising silicon and said hygroscopic second liquid onto said substrate. 
     
     
       47. The method of  claim 37 , wherein said applying comprises chemical vapor depositing said first liquid comprising silicon and said hygroscopic second liquid onto said substrate. 
     
     
       48. The method of  claim 37 , wherein said applying comprises: 
       introducing silicon-containing vapor and hydrogen peroxide vapor into said chamber; and  
       reacting said silicon-containing vapor with said hydrogen peroxide vapor to form said first liquid comprising silicon and said second liquid, wherein said second liquid comprise water.  
     
     
       49. A method of treating a semiconductor substrate in a chamber, said method comprising: 
       applying a first liquid comprising silicon and a hygroscopic second liquid onto said substrate;  
       contacting said first liquid comprising silicon and said second liquid with a third liquid which attracts said second liquid, thereby removing at least a portion of said second liquid,  
       wherein said first liquid comprising silicon comprises silicon dioxide and said first liquid further comprises a dopant selected from the group consisting of arsenic, antimony, boron, phosphorous, and gallium; and  
       separating said third liquid from said first liquid comprising silicon on said substrate.